Fuel Line Adapter - 3/8 In. Steel Compression to 3/8 In. Nylon Barbed. Fuel Line Adapters- 3/8 In. Steel to 3/8 In.(10mm) Nylon Tubing. Compression (Fitting Attachment End 1), Barb (Fitting Attachment End 2). Compression Connector; 3/8 In. Steel to 3/8 In.(10mm) Nylon Tubing. Now you can replace a damaged connector without spending time or money on the entire fuel line. But that's not the only advantage. Highly resistant to the extreme temperatures that lead to cracking, Dorman's Fuel Line Connectors prevent leaks from forming.